Vehicular parking brakes use a cable system to manually engage and release the brakes. The park brake system includes an actuation lever, such as but not limited to a handle or foot lever, for actuating a plurality of cables. The actuation lever is coupled to a front or first cable. A connecting device couples the front cable to a left rear or second cable, and a right rear or third cable. The left rear cable extends from the connecting device to a left rear brake, and the right rear cable extends from the connecting device to a right rear brake. An adjustment mechanism interconnects the actuation lever and the front cable for adjusting tension in the plurality of cables. Tightening the adjustment mechanism shortens the effective length of the first cable, thereby increasing the tension in the park cables. In contrast, loosening the adjustment mechanism lengthens the effective length of the first cable, thereby decreasing the tension in the park cables.
When the park brake system is actuated, i.e., disposed in an applied position, then the park cables are tensioned to a level sufficient to engage the brakes of the vehicle. When the park brake system is disengaged, slack is introduced into the park cables to reduce the tension in the park cables. Accordingly, when the park brake system is disengaged, the park brake system may be referred to as being in a slack position, and the amount of tension in the cables when disposed in the slack position may be referred to as a target slack tension level.
The park cables must be properly tensioned to function properly. The lever or handle moves the park cables a pre-defined distance when moving from the slack position to the applied position in order to obtain the requisite tension level in the park cables. If the park cables include excess slack, i.e., if the park cables are too long, then the park brake system will fail to achieve the requisite tension level and will not apply enough force to the brakes to properly engage the brakes. In contrast, if the park cables do not include enough slack, i.e., if the park cables are too short, then the park cables will be excessively tensioned, and will create brake drag, i.e., a continuously applied braking force. Accordingly, the tension of the park cables, i.e., the length of the park cables when in the slack position, must be properly set to the target slack tension level in order for the park brake system to function properly.